Caulking gun



FIG. 1 is a side view of a caulking gun showing my new design, the side opposite being a mirror image;

FIG. 2 is a top view;

FIG. 3 is a bottom view;

FIG. 4 is a back view, as viewed from the right side of FIG. 1; and

FIG. 5 is a front view, as viewed from the left side of FIG. 1. 

The ornamental design for a caulking gun, as shown and described. 